1. Field of Invention:
This invention relates generally to air fresheners which release an aroma into the atmosphere, and more particularly to a replaceable air freshener unit that is adherable to an automobile window or other flat substrate in the automobile to render the interior atmosphere thereof more pleasing.
2. Status of Prior Art:
As used herein, the term "aroma" or "fragrance" is not limited to perfume-like odors, but encompasses any odor that is suitable as an air freshener to condition, modify or otherwise charge the ambient atmosphere.
The aroma of perfumes and perfume-based products such as colognes and toilet waters was originally derived from the essential oil of plants. However, since the early 19th century, chemists have succeeded in analyzing many essential oils and in creating thousands of synthetics, some simulating natural products and others yielding altogether new scents. Perfumes today are largely blends of natural and synthetic scents and of fixatives which equalize vaporization and enhance pungency. In most liquid scents, the ingredients are combined with a highly volatile alcohol carrier.
The concern of the present invention is with the atmosphere in the interior of an automobile, and in this context, a fragrance emitted by an air freshener may be such as to render the atmosphere more pleasing to the occupants of the vehicle, or take the form of an aromatic stimulant to discourage the driver from falling asleep at the wheel.
My prior 1988 U.S. Pat. No. 4,720,409 discloses an air freshener of the film laminate type which is adherable to a wall tile in a bathroom or kitchen to render the atmosphere more pleasing. The same laminate, as noted in this patent, can be applied to the window of an automobile.
This film laminate includes a transparent, plastic face film impregnated with a volatile fragrance that is slowly released from the film. The concentration of the fragrance in the film is such as to result in prolonged emission. The face film is laminated to a transparent backing film in a manner which does not impair the transparency of the laminate.
Imprinted on the front surface of the backing film is artwork representing an aroma-producing object of some sort. This artwork is effectively sandwiched between the face film and the backing film and is thereby protected. The rear surface of the backing film is coated with a low tack, pressure-sensitive adhesive. Thus, the laminate may be adhered onto a smooth tile or window and later pulled therefrom when the fragrance is exhausted.
This laminate is a highly effective air freshener when applied to a bathroom or kitchen tile. But when the laminate is applied to a window of an automobile, a serious problem arises; for then the laminate is exposed to sunlight and may be subjected to a tremendous buildup of heat. In certain seasons, when a car whose windows are closed is exposed to sunlight, the interior temperature may rise well above 110.degree. F.
As noted in my prior patent, the fragrance-emitting face film is preferably made of bi-axially oriented polymeric material such as EVA (ethylene vinyl acetate), whereas the backing film is made of polyester (Mylar) which is laminated to the face film by heat and pressure or other means which will not impair the transparency of the laminate.
Bur if this laminate is subjected in an automobile to elevated temperatures, the EVA face film, because of its temperature coefficient of expansion, will then expand to a greater degree than the Mylar backing film, resulting in delamination of the laminate. Moreover, because the fragrance is impregnated throughout the entire area of the face film, when this relatively broad area is subjected to an elevated temperature, the result is an excessively rapid emission of the fragrance. An automobile interior is a confined space; and when the windows are closed, it takes a relatively small amount of aromatic vapor to charge the interior atmosphere. But if the amount of aromatic vapor exuded into this interior is excessive, the fragrance will then be too "heavy," and to this extent may be displeasing to the occupants of the vehicle.